Lignin is an attractive raw material for low-cost sustainable carbon fibres, however, the resulting mechanical properties require improvement before they can be implemented in composite applications. The mechanical properties of conventional polyacrylonitrile-derived carbon fibres depend critically on the molecular alignment induced in the polymer fibres by fibre drawing and on retention of the alignment during subsequent thermal treatments. In this study, alignment was induced in high lignin content fibres wet-spun from a low-cost ionic liquid water mixture by employing similar hot-drawing methods. 75/25 wt/wt% lignin-poly(vinyl alcohol) (lignin-PVA) fibres were continuously wet-spun from a 60/40 wt/wt% N,N-dimethylbutylammonium hydrogen sulfate, [DMBA][HSO4] water mixture, using deionised water used as the coagulant. Hot-drawn fibres with high draw ratios of up to 20 were generated at 180 °C. By careful selection of the initial extrusion diameter and the subsequent draw ratio, the influence of fibre diameter and draw ratio was systematically distinguished. The draw ratio was found to dominate the mechanical properties of the ductile precursor fibres, while the fibre diameter was more significant after stabilisation. The precursor fibres that experienced the highest draw ratios had tensile strengths of 235-249 MPa (up to four times higher than the undrawn lignin-PVA fibres) and tensile modulus of 7.5-8.2 GPa, while the fibre diameter was reduced from 64-106 μm to 15-23 μm. Wide-Angle X-ray Scattering (WAXS) studies showed that hot-drawing induced orientation and crystallisation of PVA at high draw ratios. The crystallisation and orientation of PVA was lost during the slow oxidative stabilisation at 250 °C, associated with a plateau at around 110 MPa tensile strength and 4 GPa tensile modulus for the stabilised lignin-PVA fibres, regardless of draw ratio. Improvements to the stabilisation aimed at retaining alignment are proposed.

A new class of bicontinuous nanocomposite has recently emerged based on vacuum infusion of monolithic silica aerogel with commercial epoxy resin. Here, new silica aerogel functionalisation strategies are developed to improve the interfacial bonding in such systems. Hydrophobicity is essential when forming aerogel monoliths, as moisture absorption rapidly degrades the aerogel structure leading to increased shrinkage and macroscopic cracking. Classic hydrophobisation with trimethylchlorosilane (TMCS) produces near-complete methylation of silanol groups. This inert surface prevents covalent silica-epoxy interfacial bonding and has produced relatively brittle composites when compared with discontinuous reinforcements featuring reactive interfaces. A milder hydrophobisation agent, dimethyldimethoxysilane (DMDMS), gives an unsaturated “part-methylated” silica aerogel surface through the partial conversion (77% vs. TMCS) of surface silanols to methyl-terminated groups. Part-methylated surfaces are more hydrophobic than unmodified silica aerogel (74% lower absorbed water content under ambient conditions), whilst retaining reactive silanol groups for strong interfacial bonding. Additionally, for explicit epoxide reactivity, simultaneous grafting of both DMDMS and (3-glycidyloxypropyl)trimethoxysilane (GPTMS) was achieved by varying functionalisation group ratios to produce high quality dual-functionalised “part-methylated + epoxidated” monoliths. Covalent tethering of epoxide groups was evidenced by infrared spectroscopy and gas sorption analysis. Solid state, self-condensation between the tethered epoxides and intrinsic silanols was observed when subjected to mild drying conditions. For each surface type, surface area, porosity, and drying performance were measured across a wide range of silica volume fraction in the context of bicontinuous nanocomposite formation. Overall, part-methylated aerogel constitutes a promising candidate constituent for bicontinuous silica-epoxy nanocomposites with improved interfacial adhesion.

Multifunctional structural power composites (SPCs) provide a lightweighting solution for conventional electrochemical energy storage, while offering additional mechanical capability. This work studied the anisotropic electrical response of woven carbon fibre (WCF) reinforced structural supercapacitor electrodes, i.e., plain weave, spread tow, and carbon aerogel (CAG) modified spread tow fabrics, under cyclic compaction. Experimental results show that 1 MPa compaction increased in-plane conductivity by over 60% and out-of-plane conductivity by at least five-fold for all fabrics tested. Numerical studies revealed that the intra-yarn fibre volume fraction is a critical factor for both in-plane and out-of-plane electrical performance. The predicted in-plane conductivity of woven fabrics presents a linear relationship with the intra-yarn fibre volume fraction, following a modified rule of the mixtures (ROMs). For the out-of-plane conduction, a larger number of percolating paths formed with more fibre-to-fibre contacts and fibre clusters under a higher fibre volume fraction, thus promoting the out-of-plane conductivity. Additionally, CAG modification formed a conductive CAG skin over the fabric surface, which largely reduced the in-plane electrical anisotropy of WCFs. In principle, reducing the intra-yarn free volume of WCF-reinforced electrodes provides a route towards significantly improving the electrical performance of SPCs and serves as a guidance for subsequent encapsulation and multifunctional design.

Liquid crystalline (LC) solutions of single-walled carbon nanotubes (SWCNTs) provide an attractive route to ordered fibers, films, and coatings, with exceptional multifunctional properties. Here, the formation of nematic phases, using reductive chemistry, to generate SWCNT polyelectrolytes (sodium nanotubides) as an alternative to routes based on superacids is elucidated. Strikingly, the stable mesophase domain of SWCNT polyelectrolytes extends to spontaneous LC nematic formation at a low concentration of 0.18 mg mL-1; the isotropic-nematic phase boundary is mapped out and found to relate, through the Debye length, to the effective aspect ratio in accordance with Onsager's theory. These LC SWCNT polyelectrolyte solutions are shown to allow the direct, scalable, and safer processing of macroscopic assemblies such as fibers, yarns, pastes, and textile coatings, which are effective for transmitting electrical signals (electrical conductivity ∼1.0 MS m-1). These processes are illustrated by a range of electronic textile devices built around SWCNT-coated cotton, connected by SWCNT yarns. Acid-free processing is compatible with a much broader range of equipment, functionalization chemistries, and substrates by providing many opportunities for development.

The ordering of ions and solvent molecules around nanostructures is of profound fundamental importance, from understanding biological processes to the manipulation of nanomaterials to optimizing electrochemical devices. Classical models commonly used to describe these systems treat the solvent simplistically, an approach that endures, in part, due to the extreme difficulty of attaining experimental measurements that challenge this approximation. Here we perform total neutron scattering experiments on model systems-concentrated amide solutions of negatively charged carbon nanotubes and sodium counterions-and measure remarkably complex intermediate-range molecular solvent ordering. The charged surface orders the solvents up to similar to 40 & Aring;, even beyond its dense concentric solvation shells. Notably, the molecular orientation of solvent in direct contact with the nanotube surface itself is distinct, lying near-parallel and not interacting with desolvated sodium counterions. In contrast, beyond this layer the ordering of solvent is perpendicular to the surface. Our results underscore the critical importance of multibody interactions in solvated nanoscale systems and charged surfaces, highlighting competing ion/surface solvation effects.

High-throughput methods can accelerate the development of metal alloys and (nano)composites, both empirically and as input to computational methods. This study introduces a new route to fabricating composite wires with longitudinally varying composition using the byproduct of stationary-shoulder friction stir channelling (SS-FSC); this sample format is attractive for a variety of rapid read-out options in the future. The concept is illustrated by preparing Mg composite wires with a longitudinally graded concentration of SiC-particles. Spark plasma sintering (SPS) was used to encode a step-change in SiC concentration within a feedstock billet. Subsequent SS-FSC transformed this discrete compositional step into a continuous, graded extruded wire. Micro-structural analysis revealed significant grain refinement from the SPS billet (44.3 f 2.3 mu m) to the SS-FSC wire (7.4 f 0.5 mu m), with even finer grains in SiC-loaded regions (5.1 f 0.5 mu m), attributed to particle-stimulated nucleation. Mechanical characterisation confirmed a hardness increase, from 65.8 f 1.2 HV3 to 68.9 f 2.7 HV3 (high SiC-content). This proof-of-concept study confirms the effectiveness of SS-FSC in producing high-quality wires with tailored microstructural and mechanical gradients. Additional compositions could be readily multiplexed in the original billet, providing a robust high-throughput technique for comprehensive structure-property investigations of advanced alloys and composites.

This study investigates the mesoscale deagglomeration mechanisms of multi-walled carbon nanotubes (MWCNTs) in aqueous solutions with and without added surfactant (Triton X-100), using high-speed imaging and numerical simulations. High-speed observations revealed that within the cavitation zone (CZ, defined as the region of high bubble intensity), the addition of surfactant had no obvious effects on deagglomeration behaviour, with most agglomerates remaining intact and only occasional fragmentation events observed. In contrast, in regions outside the CZ, surfactant addition significantly increased the number and stability of microbubble clusters, leading to more frequent interactions with MWCNT agglomerates. Numerical simulations performed under matched experimental conditions confirmed a spatial variation in bubble dynamics, with enhanced microbubble formation and persistence in surfactant-containing solutions, particularly at distances away from the sonotrode. These findings provide direct mechanistic evidence that surfactant not only stabilises dispersed CNTs but also facilitates microbubble-mediated deagglomeration outside the CZ. The results highlight the role of structured bubble activity in extending the effective dispersion region during ultrasonication, offering insight into the optimisation of CNT processing in surfactant-assisted systems.

Post-synthetic diameter-selective separation of nanotubular structures has relied on exohedral interactions; a diameter-dependent enrichment via endohedral interactions for the purification of bulk single-walled carbon nanotubes (SWCNTs) remains unexplored. This paper describes a novel diameter-selective supramolecular selfassembly motif for nanotube enrichment via fullerene (C60) encapsulation by SWCNTs. C60-grafted silicon wafers and silica particles were used for the diameter-selective self-assembly and enrichment/separation of individualized SWCNTs, respectively. C60 grafting to silica substrates was performed via the addition of azide-terminated silane precursors, followed by the cycloaddition of azides with C60 to azafulleroids. Atomic force microscopy was used to determine the diameter dependency of the method. The diameter-sorted SWCNTs were further characterized via ultraviolet-visible-near-infrared spectroscopy and Raman spectroscopy. The method presented here was found to select SWCNTs with diameters of approximately 1.4-1.7 nm, with a central cavity matched to the diameter of C60. Self-assembly and enrichment/separation of other nanotubular structures are anticipated with this approach.

beta-SiC nanowhiskers (SiCwh) are promising reinforcements for magnesium matrix nanocomposites (MgMNCs) due to their high strength and compatibility with Mg-Al alloys. In this study, SiCwh were successfully incorporated into AZ91 alloy via melt stirring. Synchrotron-based phase contrast tomography (PCT) was employed to characterise their three-dimensional dispersion. Notably, the formation of T2-Al2MgC2 ternary carbides was observed at the SiCwh-matrix interface, indicating interfacial reactions during processing. Atomic-resolution transmission electron microscopy (TEM) revealed nanoscale segregation within these carbides, suggesting a complex growth mechanism. The integration of TEM, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) further identified crystallographic orientation relationships (ORs) between SiCwh, T2-Al2MgC2, and alpha-Mg. These ORs suggested that T2-Al2MgC2 promotes heterogeneous nucleation and grain refinement in the matrix. Moreover, interfacial reactions were found to enhance wetting and dispersion of SiCwh, improving their distribution throughout the matrix. These findings provide new mechanistic insights into interfacial phase formation and its influence on microstructure evolution. Controlled interfacial reactions can be leveraged to optimize dispersion and refine grain structure in MgMNCs. Given the simplicity and scalability of melt stirring, this approach offers a promising route for industrial production of SiC-reinforced Mg composites with enhanced properties.

Commercial lithium-ion battery (LIB) electrodes traditionally comprise a homogeneous layer of stochastically mixed constituent materials. However, a significant barrier to cell performance is attributed to the architecture of the electrode; the trade-off between useful capacity and rate capability limits the cell performance during fast charging or discharging. This study develops a continuum model to emulate the behaviour of these electrodes. It presents optimal electrode thickness and active material (AM) volume fraction values that maximise cell performance for slurry-cast electrodes. Finally, the study demonstrates that by patterning the electrode architecture, volumetric energy density can be significantly improved, subject to manufacturing constraints, and provides quantitative design guidelines for future study.

The ability of fibre reinforced composites to deform with a non-linear stress-strain response and gradual, rather than sudden, catastrophic failure is reviewed. The principal mechanisms by which this behaviour can be achieved are discussed, including ductile fibres, progressive fibre fracture and fragmentation, fibre reorientation, and slip between discontinuous elements. It is shown that all these mechanisms allow additional strain to be achieved, enabling a yield-like behaviour to be generated. In some cases, the response is ductile and in others pseudo-ductile. Mechanisms can also be combined, and composites which give significant pseudo-ductile strain can be produced. Notch sensitivity is reduced, and there is the prospect of increasing design strains whilst also improving damage tolerance. The change in stiffness or visual indications of damage can be exploited to give warning that strain limits have been exceeded. Load carrying capacity is still maintained, allowing continued operation until repairs can be made. Areas for further work are identified which can contribute to creating structures made from high performance ductile or pseudo-ductile composites that fail gradually.

Commercial lithium-ion battery electrodes today are manufactured by slurry casting active material powder onto a metal current collector foil. This manufacturing process has become embedded over recent decades but limits commercial cell performance. This paper presents patterning of a monolithic active material sheet as an alternative to slurry casting. The concept is proven experimentally by laser drilling a pyrolytic graphite sheet to increase the gravimetric active material capacity from 10 mA h g-1- 1 to 450 mA h g-1,- 1 , when used as a negative lithium-intercalation electrode. Cell-level calculations show that, without changing the chemistry, a pyrolytic graphite sheet electrode with a hexagonal array of 5 m m diameter, 20 m m pitch channels could increase the gravimetric energy density of a LGM50 cell by 22% to 322 W h kg- 1 . By moving beyond slurry casting, patterned monolithic electrodes could enable batteries with lower cost, reduced energy intensity, and enhanced performance.

Fragmentation of high modulus carbon fibres is relevant to the failure mechanisms of advanced polymer matrix composites in compression. In situ spatially-resolved Raman spectroscopy during the fragmentation of model single fibre composites is used to map local stress distributions during failure events. The characteristic graphitic band (the G band) located around 1580 cm- 1 is associated with the in-plane carbon-carbon bonds; this band shifts its position, and can be calibrated, with the local axial stress in the fibre. The analysis maps the evolution of local stresses with increasing overall composite compression strain, identifying a series of critical events, including fibre fracture, interfacial debonding, and the formation of inter-fragment 'wedges'. Fitting shear lag models provides interfacial shear strength values. Multiple failure maps of two examples of high modulus PAN carbon fibres (M46J and M55J) demonstrate the possibility of local fragment bending due to fragment end contact. A timeline of potential fragmentation events is proposed for carbon fibres undergoing compression.

The ligand chemistry of colloidal semiconductor nanocrystals mediates their solubility, band gap, and surface facets. Here, selective organometallic chemistry is used to prepare small, colloidal cuprous oxide nanocrystals and to control their surface chemistry by decorating them with metal complexes. The strategy is demonstrated using small (3-6 nm) cuprous oxide (Cu2O) colloidal nanocrystals (NC), soluble in organic solvents. Organometallic complexes are coordinated by reacting the surface Cu-OH bonds with organometallic reagents, M(C6F5)(2), M = Zn(II) and Co(II), at room temperature. These reactions do not disrupt the Cu2O crystallinity or nanoparticle size; rather, they allow for the selective coordination of a specific metal complex at the surface. Subsequently, the surface-coordinated organometallic complex is reacted with three different carboxylic acids to deliver Cu-O-Zn(O2CR') complexes. Selective nanocrystal surface functionalization is established using spectroscopy (IR, F-19 NMR), thermal gravimetric analyses (TGA), transmission electron microscopy (TEM, EELS), and X-ray photoelectron spectroscopy (XPS). Photoluminescence efficiency increases dramatically upon organometallic surface functionalization relative to that of the parent Cu2O NC, with the effect being most pronounced for Zn(II) decoration. The nanocrystal surfaces are selectively functionalized by both organic ligands and well-defined organometallic complexes; this synthetic strategy may be applicable to many other metal oxides, hydroxides, and semiconductors. In the future, it should allow NC properties to be designed for applications including catalysis, sensing, electronics, and quantum technologies.

beta-SiC nanoparticles are one of the most common reinforcements in Mg-Al alloy matrix nanocomposites (MgMNCs). The interfacial interactions between beta-SiC and the alloy matrix are complex due to the occurrence of new phases and the fine scale of the 3D architecture. This study aims to explore the feasibility of using synchrotron Scanning Transmission X-ray spectro-Microscopy (STXM) to investigate such interfacial interactions and acquire reference X-ray Absorption Spectroscopy (XAS) data for some common interphase crystals present within the composites, which are not readily available. Throughout this study, a reliable procedure for collecting STXM data on samples derived from MgMNCs was developed, and reference XAS spectra for alpha-Mg, beta-Mg17Al12, T2-Al2MgC2, Mg2Si and MgO present in MgMNCs were collected. The accessibility of STXM and spatially resolved XAS spectrum is not only useful for nanocomposite alloy research but applicable widely across the magnesium alloy research community when identifying and quantifying the phases with complex crystal structures and oxide states.

Structural power composites, a class of multifunctional materials, may facilitate lightweighting and accelerate widespread electrification of sustainable transportation. In the example considered in this paper, structural power composite fuselage components could provide power to open aircraft doors in an emergency and thus reduce or eliminate the mass and volume needed for supercapacitors currently mounted on the doors. To demonstrate this concept, an 80 cm long multifunctional composite C-section beam was designed and manufactured, which powered the opening and closing of a desktop-scale composite aircraft door. Twelve structural supercapacitor cells were made, each 30 cm x 15 cm x 0.5 mm, and two stacks of four cells were integrated into the web of the beam by interleaving and encasing them with low-temperature-cure woven carbon fibre/epoxy prepreg. This article culminates by considering the engineering challenges that need to be addressed to realise structural power composite components, particularly in an aerospace context.

Interpenetrated, bicontinuous nanocomposites are formed by fully infusing monolithic mesoporous silica (silica aerogel) with epoxy resin. The long-range connectivity of the silica network facilitates direct load transfer and enforces sample homogeneity. The silica networks are prepared using sol-gel chemistry, informed by new phase diagrams, adapted to maximise reinforcement content in the subsequent bicontinuous composite. The infusibility of the aerogels is correlated to pore characteristics determined by gas sorption, as a function of silica aerogel density. Silica reinforcement loadings of up to 22 silica vol.% are fully consolidated, with only a modest reduction in glass transition temperature and no change in cure conditions. The reinforcement improves both hardness (+23 %) and reduced modulus (+17 %) of the baseline resin. These properties increase with aerogel content via a power law relationship which demonstrates the direct role of the connected silica phase as a reinforcing network and motivates future studies to extend the applicable range.

A white light-activated bactericidal coating consisting of acrylic latex, Zinc oxide nanoparticles (ZnO NPs) and crystal violet (CV) was produced through a two-step dipping process.